已知sin(a+π/6)+cosa=4/5倍根号3,则sin(a+π/3)=

问题描述:

已知sin(a+π/6)+cosa=4/5倍根号3,则sin(a+π/3)=

sin(a+π/6)+cosa
=sina*(v3/2)+cosa*(1/2)+cosa
=v3[sina*(1/2)+cosa*(v3/2)]
=v3sin(a+π/3)
=(4/5)*v3,
——》sin(a+π/3)=4/5.